nuclear magnetic resonance experiments for chemical reaction monitoring under spin diffusion conditions.

osity-enhanced spectroscop () offers a new way to analyze complex mixtures of time-varying composition. This communication reports the use of the viscous binary solvent DMSO-/water to induce NMR spin diffusion for chemical reaction monitoring and real-time characterization of a 3-substituted 4-hydroxycoumarin derivative and its side-product.

Budmunchiamines as a Potential Adjuvant for Rejuvenating Phenicol Activities towards -Resistant Strains.

The continuous emergence of bacterial resistance alters the activities of different antibiotic families and requires appropriate strategies to solve therapeutic impasses. Medicinal plants are an attractive source for researching alternative and original therapeutic molecules. In this study, the fractionation of natural extracts from and the determination of antibacterial activities are associated with molecular networking and tandem mass spectrometry (MS/MS) data used to characterize active molecule(s).

Use of Diethanolamine as a Viscous Solvent for Mixture Analysis by Multidimensional Heteronuclear NMR Experiments.

Diethanolamine/DMSO- as a viscous binary solvent is first reported for the individualization of low-polarity mixture components by multidimensional heteronuclear NMR experiments under spin diffusion conditions. Solvent viscosity induces the slowing down of molecular tumbling, hence promoting magnetization transfer by dipolar longitudinal cross-relaxation. As a result, all H nuclei resonances within the same molecule may correlate in a 2D nuclear Overhauser effect spectroscopy (NOESY) spectrum, giving access to mixture analysis.

ViscY NMR experiments in phosphoric acid as a viscous solvent for individualization of small molecules within mixtures by spin diffusion.

The analysis of small molecules within complex mixtures is a particularly difficult task when dealing with the study of metabolite mixtures or chemical reaction media. This issue has fostered in recent years an active search for effective and practical solutions. In this context, the ViscY NMR approach has been recently proposed.

Mixture Analysis in Viscous Solvents by NMR Spin Diffusion Spectroscopy: ViscY. Application to High- and Low-Polarity Organic Compounds Dissolved in Sulfolane/Water and Sulfolane/DMSO- Blends.

The sulfolane/water and sulfolane/DMSO- binary NMR solvents are reported for the individualization of mixture components by spin diffusion when molecular tumbling is slow due to solvent viscosity, thus strongly favoring magnetization transfer by dipolar cross-relaxation. All H nuclei resonances within the same molecule tend then to correlate in a 2D NOESY spectrum, opening the way to mixture analysis. Till now, analysis of organic compounds by NMR spin diffusion in viscous solvents involved H, C, N, and F.